A conventional method for manufacturing a flat, rectangular foam cushion or pad further includes a flat cushion making module which is conventionally comprised of two linear conveyors, each with a flat belt, mounted so that their belts are opposed and substantially parallel to each other.
Known in the art is a process of making flat, rectangular, foam cushions (sometimes referred to as “pads”), as in the formation of pads in the foam packaging industry. Current techniques and methods used by existing pad molders are described as follows: Contemporary Methods for Manufacturing Flat, Rectangular, Foam Cushions                a. The opposing conveyor belts are spaced apart to the desired thickness of the ultimate flat foam cushion—usually between one to two inches of thickness.        b. Each conveyor belt moves at substantially the same speed, with one conveyor rotating in a clockwise direction and the other rotating in a counterclockwise direction so that the pads are pulled into the gap by the conveyors relative motions. The conveyors start and stop simultaneously so that they move as a synchronized pair to prevent shearing of the flat foam cushions as they move.        c. The conveyors conventionally are set up in either a vertical or horizontal orientation.        
The foam filled bags exit the FIB bagger which is positioned so that the descending bags will be dispensed in the general direction of the gap between the belts of the moving conveyors. In reality, current flat cushion molding systems require an operator to feed the bags (that come down or out from the FIB system) into the gap between the conveyors. Otherwise, the not yet cured bags have a tendency to fold over or otherwise miss-feed into the conveyors causing the foam bags to burst within the machine. This is commonly known as a “foam-up”.
Thus, in such a conventional feed operation;                a. Both belts advance as the bag exits the FIB machine to essentially pull or drag the foam filled bag into the gap between the conveyor belts as the bag exits from the output portion of the FIB system.        b. For satisfactory operation, it is conventional in the industry that a human operator assists in getting the bags to feed properly into the conveyor gap.        c. The foam filled bag must be pulled into and fully constrained by the opposing conveyor belts early in the foam expansion cycle so that the rising foam inside the bag forms itself to the gap (sized to the desired cushion thickness) between the opposing belt surfaces.        d. If the foam expands excessively prior to the bag getting pulled into the gap between the conveyors, the conveyors may not be able to pull the forming bag in, and it will jam up the entry zone essentially stopping the process until the jam is cleared.        e. In conventional systems the process timing is mainly determined through testing and experimentation. The timing of the process is generally based on the type of foam being used, the speed of the conveyors, and other factors.        
The foam rises and solidifies while contained between the conveyor belts.                a. The foam expansion in the bag is restricted and controlled by the distance of separation between the belts. For example, if the belts are spaced one inch (2.54 cm) apart the final flat cushion will be one inch (2.54 cm) thick.        b. Typical flat cushion thicknesses range between ½ inch (1.26 cm) to 3 inches (6.62 cm).        c. Typical flat foam cushion molding systems have built-in means of adjusting the spacing between the conveyors while maintaining them in a parallel orientation. This is usually done with a manually driven crank and chain arrangement.        d. This allows the flat cushion user to adjust cushion thickness to suit the application.        
The expanding foam will generate a pressure in the range of 3 pounds per square inch so the support structures of the forming conveyors must be robust enough to handle these loads without undue deflection.                a. To maintain flatness each belt in conventional systems features a stationary, rigid, and flat backer plate mounted directly behind the belt.        b. The belts slide over the backer plates so the plates require a low coefficient of friction to minimize drag.        c. The backer plates and their support structures must be rigid and strong so as to remain essentially flat under the loads generated by the pressure of the rising foam.        d. The rigid backer plates insure that the finished foam cushions will be basically flat.        e. Also, the drive motors on each belt must be strong enough to move the belts with high friction loads generated by the expansion of the foam pushing the belt into its backer plate. These loads can be in the hundreds of pounds and the required motors may be larger than what would typically be associated with the size of conveyor involved.        
The flat foam cushions move, as they cure and harden, contained between the belts along their axis of motion.                a. The curing flat cushions are confined within the gap between the conveyor belts until the foam is sufficiently cured to retain its intended shape as flat and rectangular when removed from between the conveyors.        b. If the flat foam cushions are taken out from between the pair of conveyors too soon the foam will not be sufficiently cured, and the foam cushions will not hold their desired flat shape.        
Flat cushion width is primarily determined by the width of the film used to form the flat cushion. Typical widths range from 12 to 30 inches.
After the foam in the cushion has cured sufficiently so as to retain its flat shape, the conveyors will move it along until it drops out at the end of its travel.                a. As they fall out of the conveyor output, the flat foam cushions can be collected in storage or accumulator bins—they can be used by a packer—or they can fall onto another conveyor to take them away for use or storage at a remote location.        
The flat foam cushion production rate can be increased by lengthening the conveyors.                a. It generally takes at least 20 seconds for a typical illustrative cushion to cure to a point that it can be removed from the constraining conveyor belts. For some of the denser foam formulations this minimum time can be much longer than the aforementioned 20 seconds as in one minute.        b. Longer belts allow for more curing time per cushion and faster production rates.        
Longer belted systems will have a greater flat cushion per minute output up to the limitations of the bag making module.                c. It is believed that there exists in illustrative conventional systems flat foam cushion molders capable of running at up to 26 cushions per minute but in reality running at the limiting factor of the output rate of the bag making module is typically the norm.        
The conventional systems generally suffer from the drawback of not being sufficiently generally fully automated in the formation of flat foam cushions or well suited for running without a human operator.                a. That is, it is considered by Applicants that suitable flat foam cushion production systems in the industry and using current technology are of a nature that requires monitoring and assistance from an operator to prevent foam ups.        b. The most common problem occurs when a corner or an edge of a bag catches and gets folded over as it enters the gap between the molding conveyors.        c. When the film is folded, the effective bag volume is restricted and has a lesser capacity with which to contain the expanding foam which has already been dispensed in the quantity required for the anticipated bag volume.        d. When this happens, a bag rupture and a possible explosion of foam can occur if the available bag volume cannot hold the amount of foam dispensed into the bag.        e. These ruptures and/or explosions, often called foam-ups, can be especially messy and difficult and time consuming to clean.        f. Another problem is that the flat cushions, if not properly oriented, will jam inside the conveyor. These jams can also cause a foam-up as succeeding bags continue to enter the conveyor system and an operator is not available to shut the system down in a timely manner.        
Problems such as those described above are common in the foam cushion packaging industry such as in the production of cured polyurethane flat panel packaging cushion inserts.
Problems such as those described above for the foam cushion packaging industry can also be experienced in the production of other “pad” components (e.g., enclosures (typically flexible) that enclose material which is placed in the enclosure (which material is typically flexible at the outset and forms as to be less flexible such as in a curing or solidifying during cooling down or setting, etc.)). Examples of other packaging industries that can experience problems such as those described above include, for example, the food industry, the chemical industry (e.g., plastics) and construction powdered mixes, etc., although expanding types of materials are the more problematic.